Potential biological attacks against large scale civilian populations have become an important issue in homeland security. By way of example, the anthrax cases in the United States in 2001 and the ricin case on Capitol Hill in 2004 have proven that the threat of a biological attack is real. In order to thwart any potential biological attack, the development of a civilian biodefense plan is crucial. Consequently, there has been an enormous effort to develop practical and efficient biosensors in recent years.
Most present biosensors take advantage of biologically active materials for high sensitivity and selectivity. In general, the biosensor includes a biorecognition structure (e.g., a membrane) in contact with or interrogated by a transducer. The biologically active material recognizes a particular biological molecule through a reaction, specific adsorption, or other physical or chemical process, and the transducer converts the output of this recognition into a usable signal, usually electrical or optical. Many approaches have been explored to achieve ultra-sensitive detection of bio-species. These biodetection approaches can be categorized as either an engineering-oriented approach or a biological-oriented approach. In other words, most biodetection schemes are either based on relatively complex electronic, photonic and/or electrochemical methods or more elegant biomolecular methods (e.g. enzyme linked immunosorbent assay, or ELISA) typically with an optical or spectrometry-based readout.
By way of example, one process utilizes photonics integrated on a microchip to study the interaction between the optical field and the target bio-analyte. Because most biorecognition processes occur in an aqueous ambient, this approach requires the integration of photonics, highly sensitive microelectronics and microfluidic systems on a single microchip. The use of ion-channel switches as biosensors has also been explored, but the bioelectronic interface is a delicate one. Often, when an approach promises very high sensitivity, the output signal from the biorecognition is very small, thus requiring extremely highly-sensitive on-chip microelectronics for signal amplification, processing and wireless transmission. The high demand of these approaches on system integration and high sensitivity photonics and electronics circuitry presents a big challenge to the biosensors in terms of cost, reliability and power consumption. The more biomolecular based approaches, like ELISA, are simple, but typically require a macro scale spectrometry system to quantify the output.
Therefore, it is a primary object and feature of the present invention to provide a bioagent detection device that is highly sensitive and selective, has a quick response time (on the order of one hour or less) and generates few false alarms.
It is a further object and feature of the present invention to provide a bioagent detection device that is small in size and weight and is inexpensive to manufacture.
It is a still further object and feature of the present invention to provide a bioagent detection device that possesses wireless communication capability over a large area span.
It is a still further object and feature of the present invention to provide a bioagent detection device that is able to operate in different environments, such as in air and in water, without premature failure.
In accordance with the present invention, a detection device is provided for detecting the presence of a bioagent in a fluid. The detection device includes a body defining a first chamber for accommodating the fluid therein and a second chamber. A detection structure is disposed in the second chamber of the body. The detection structure generates a predetermined signal in response to exposure to the fluid. A valve interconnects the first and second chambers. The valve opens in response to the presence of the bioagent in the fluid in the second chamber.
The valve may be fabricated from a polymeric material that dissolves in response to exposure to the bioagent. The detection structure may include a microcapacitor having first and second terminals for connecting the detection structure to a signal detection circuit, as well as, first and second spaced electrodes. With the valve open, fluid flows into the second chamber. The microcapacitor has a first capacitance in the absence of fluid in the second chamber and a second capacitance with the fluid in the second chamber. The body may also define a channel having an input communicating with the first chamber and an output communicating with the second chamber. The valve includes a dissolvable member in the first chamber overlapping the input to the channel.
The body may also define a third chamber. A second detection structure may be disposed in the third chamber of the body. The second detection structure generates a predetermined signal in response to exposure to the fluid. A second valve interconnects the first and third chambers. The second valve opens in response to the presence of a second bioagent in the fluid in the first chamber. Alternatively, the second valve may open in response to the presence of the bioagent in the fluid in the first chamber. It is contemplated for the first valve to open a first predetermined time period after exposure to the bioagent and the second valve to open a second predetermined time period after exposure to the bioagent and for the first predetermined time period to be less than the second predetermined time period.
In accordance with a further aspect of the present invention, a detection device is provided for detecting the presence of a bioagent in a fluid. The detection device includes a body defining a first chamber for accommodating the fluid therein and a second chamber. A first valve is disposed in the body. The first valve has a first closed configuration wherein the first and second chambers are isolated and a second open configuration wherein the first and second chambers communicate. A first detection structure is disposed in the second chamber. The first detection structure generates a predetermined signal in response to exposure to the fluid.
The body further defines a channel extending between the first and second chambers. The channel has an input communicating with the first chamber and an output communication with the second chamber. The first valve overlaps the input to the channel. The first valve includes a polymeric material isolating the first and second chambers. The polymeric material dissolves in response to exposure to the bioagent.
The detection structure includes a microcapacitor having first and second terminals for connecting the detection structure to a signal detection circuit. The second chamber accommodates the flow of fluid therein with the valve in the open configuration. The microcapacitor has a first capacitance in the absence of fluid in the second chamber and a second capacitance with the fluid in the second chamber.
The body may also define a third chamber. A second valve is disposed in the body. The second valve has a first closed configuration wherein the first and third chambers are isolated and a second open configuration wherein the first and third chambers communicate. A second detection structure is disposed in the third chamber for generating a predetermined signal in response to exposure to the fluid.
The first valve is formed from a first polymeric material that isolates the first and second chambers. The first polymeric material dissolves in response to exposure to a first bioagent. However, the second valve may be formed from a second polymeric material that isolates the first and third chambers. The second polymeric material dissolves in response to exposure to a second bioagent.
It is contemplated for the first valve to open a first predetermined time period after exposure to the bioagent and for the second valve to open a second predetermined time period after exposure to the bioagent. The first predetermined time period is less than the second predetermined time period.
In accordance with a still further aspect of the present invention, a method is provided for detecting the presence of a bioagent in a fluid. The method includes the step of passing the fluid into a body defining first and second chambers. The first and second chambers are isolated from each other by a first valve. The first valve opens in response to the bioagent in the fluid so as to allow fluid to flow into the second chamber. A signal is generated in response to the presence of fluid in the second chamber.
The first valve is formed from a polymeric material that dissolves in response to exposure to the bioagent and the step of generating the signal includes the additional step of providing a microcapacitor having an initial capacitance in the second chamber. The capacitance of the microcapacitor is varied in response to the presence of fluid in the second chamber and the change in capacitance is detected. The method of the present invention may also include the additional steps of providing a third chamber in the body and opening a second valve in response to a second bioagent in the fluid so as to allow fluid to flow into the third chamber. Thereafter, a second signal is generated in response to the presence of fluid in the third chamber. Alternatively, the second valve is opened in response to the bioagent in the fluid so as to allow fluid to flow into the third chamber. Thereafter, the signal is varied in response to the presence of fluid in the third chamber.
The first valve may be formed from a first polymeric material that isolates the first and second chambers. The first polymeric material dissolves in a first predetermined time period in response to exposure to the bioagent. In addition, the second valve may be formed from a second polymeric material that isolates the first and third chambers. The second polymeric material dissolves in a second predetermined time period in response to exposure to the bioagent.